Shutter mechanism for slide projectors



.J. ANTOS SHUTTER MECHANISM FOR SLIDE PROJEQTORS March 14, 1967 10Sheets-Sheet 1 Original Filed Nov. 9', 1962 ZNVEN roe 3e 5 E'PH A-TosATTYS.

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SHUTTER MECHANISM FOR SLIDE PROJECTORS Original Filed Nov. 9, 1962 10Shaets-fiheet v 152' I60 155 wt Kve INvENToR JQSEPH Ann-as Tws.

March 14, 1967 J. ANTOS 3,308,718

SHUTTER MECHANISM FOR SLIDE PROJECTORS Original Filed Nov. 9, 1962 10Sheets-Sheet 8 iiiii INVENTOR Jose-PH AN'ros m MAD/Madam Arws.

March l4, 1967 J, NTos 3,308,718

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SHUTTER MECHANISM FOR SLIDE PROJECTORS Original Filed Nov. 9, 1962 10Sheets-$heet 10 IN v5 NTOR JOSEPH Aw'ros A'rrvs,

United 7 States Patent 3,308,718 SHUTTER MECHANISM FOR SLIDE PROJECTORSJoseph Antos, Rte. 1, Box 18A, Jones Road, Big Rock, II]. 60511 Originalapplication Nov. 9, 1962, Ser. No. 236,614, now Patent No. 3,264,937,dated Aug. 9, 1966. Divided and this application Dec. 15, 1965, Ser. No.514,085

16 Claims. (Cl. 88-26) The present application is a divisionalapplication based on the copending application of Joseph Antos, Ser. No.236,614, filed Nov. 9, 1962, now Patent No. 3,264,937.

The present invention relates in general to slide projecting apparatusand, more particularly, to an improved shutter mechanism for slideprojectors of the type employing twin optic-a1 systems. In its principalaspects, the invention is concerned with an improved shutter mechanismof the foregoing type which permits, on a selective basis, eithersimultaneous image projection from both optical systems for use inprojecting stereo or wide screen pictures or, alternatively, alternateimage projection from the twin optical systems and wherein imagesprojected alternately from th twin systems can be selectively blendedinto one another over a controllable blending period or wherein thechangeover between display of alternate images takes place substantiallyinstantaneously, thus permitting the projection of a substantiallycontinuous screen image with a wide variety of special effects.

During recent years, the general public has displayed an ever increasinginterest in the medium of slide projection and, as a result, manyprojection devices have been manufactured for automatically handlingslides. However, such devices have been subject to many operatinglimitations which have made slide viewing less enjoyable for the viewingpublic. Merely by way of example, with conventional slide projectionequipment, the viewer is subjected to annoying blackouts on the screenbetween slide changes. Moreover, such equipment generally has limitedslide capacity and requires expensive and bulky storage facilities forthe slides. One important and particularly vexing problem has been thediificulty encountered in preparing programs when slides are to be addedto, or removed from, a previous program. In an effort to eliminate theproblem of blackouts between slide changes, it has heretofore been thegeneral practice to combine standard projectors or mechanisms intopairs. However, this has resulted in bulky and heavy equipment, awkwardoperations, and limited screen effects. Additionally, such duplicationof standard equipment adds appreciably to the cost of the equipmentinstallation.

It is a general aim of the present invention to provide an improved andhighly versatile shutter mechanism for slide projectors of the typeemploying twin optical systems wherein images may be projectedsimultaneously from both systems so as to permit stereo and wide screeneffects or, alternatively, so that images may be projected alternatelyfrom the twin optical systems with the changeover from one to the othersystem occurring either instantaneously or over a controlled blendinginterval, all at the control of the projectionist. While not so limitedin its application, the invention will find especially advantageous usein the projection of images upon a screen from slides fed seriatim froma single stack and where the images from such slides may be selectivelyblended into one another, yet wherein the slides are restacked afterviewing in the same order in readiness for the next showmg.

Another object of the invention is to provide a shutter mechanism forslide projectors which permits of visual display of images projectedfrom a plurality of slides in successive order, yet wherein any givenimage may be se- 3,308,718 Patented Mar. 14, 1967 lectively faded in andout, and where successive images may be selectively blended together fordifferent blending intervals so as to produce an interesting andpleasing program presentation.

It is a correlative object of the invention to provide a shuttermechanism for an automatic image blending slide projection apparatuswhich may be readily adjusted to produce substantially instantaneouschanging of consecutive slides, yet which is characterized by itssimplicity, economy of fabrication and reliability in operation.

In another of its important aspects, it is an object of the presentinvention to provide a highly versatile shutter mechanism for imageblending slide projection apparatus of the type having twin opticalsystems which may be selectively utilized alternately to project imagesfrom slides in successive order, or utilized simultaneously to produceeither superimposed images or side-by-side images from two slides.

More specifically, it is an object of the invention to provide animproved shutter mechanism for image blending projectors which ischaracterized by its ability to alterna'tely open and close one of apair of twin optical systems while simultaneously closing and openingthe other of such systems, thus permitting selective image blending ofthe slides present in the twin systems at any given time, yet whereinthe operator may readily adjust the twin optical systems to againproject an image previously projected from the preceding slide, andwherein the change from one slide to another can be substantiallyinstantaneous or where the operator can selectively'blend the projectedimages together for variable intervals. As a consequence of attainingthis objective, the operator can readily produce a wide variety ofspecial effects such, for example, as the momentary flash of lightning,which effects are unusual and pleasant to the viewer.

Other objects and advantages of the invention will become apparent asthe following description proceeds, taken in conjunction with theaccompanying drawings, in which:

FIGURE 1 is a perspective view of a silent slide projection apparatusembodying the features of the present invention, here illustrating theapparatus with two slide magazines in operative position, one of whichis used for feeding slides seriatim to the optical systems and the otherof which is used for receiving slides seriatim following projection ofthe image therefrom;

FIG. 2 is a perspective view of one of the slide magazines shown in FIG.1, here depicting the magazine loaded with slides;

FIG. 3 is a perspective view of the slide retainer which is slidablymounted in the magazine shown in FIG. 3;

FIG. 4 is a perspective view of a magazine cover for the slide magazineshown in FIG. 2;

FIG. 5 is a vertical cross-section through the slide magazine, hereillustrating the magazine with the cover and slide retainer in place;

FIG. 6 is a plan view of the projector mechanism shown in FIG. 1, hereillustrating the mechanism with the cover, base and slide magazinesremoved;

FIG. 7 is an elevational view illustrating the right side of themechanism shown in FIG. 6 with a plurality of slides mounted in the feedhopper;

FIG. 8 is a fragmentary sectional view taken substantially along theline 88 of FIG. 6 and illustrating particularly the details of the slidechanging mechanism just prior to changing of the slides;

FIG. 9 is a sectional view similar to FIG. 8, here illustrating theslide changing mechanism just after initiation of a slide changingcycle;

FIG. 10 is a fragmentary elevation of a portion of the left hand side ofthe projector with cover and base removed, and illustrating particularlythe control linkage for actuating the slide changing mechanism;

FIG. 11 is a fragmentary rear elevational view partly in section, of theslide changing and transfer mechanism;

FIG. 12 is a sectional view taken substantially along the line 12-12 inFIG. illustrating particularly the details of the slide transfermechanism with slides positioned at the apertures in both opticalsystems and in a central feed position;

FIGS. 13 through 16 are fragmentary sectional views similar to FIG. 12and illustrating particularly the sequential positions of the slidetransfer mechanism during a complete slide changing cycle;

FIG. 17 is a perspective view of the twin shutter mechanisrns of thepresent invention together with their associated control linkage; 7

FIG. 18 is a fragmentary perspective view similar to FIG. 17 and partlyin section, here showing the twin shutters in reversed position;

FIG. 19 is a fragmentary perspective view similar to FIGS. 17 and 18,here showing the twin shutters positioned for simultaneously projectingimages from two sides;

FIG. 20 is a front view of a portion of the projector mechanism takensubstantially along the line 2020 of FIG. 6

FIG. 21 is a sectional view taken substantially along the line 2121 ofFIG. 17 and illustrating the details of the clutch actuating mechanism;

FIG. 22 is a fragmentary plan view, partly in section, illustratingparticularly the details of the slide dispensing hopper and the clutchmechanism;

FIG. 23 is a schematic wiring diagram of some of the controls used withthe projector shown in FIG. 1, and also illustrating in diagrammaticform a sound control base which can be used in conjunction with theprojector apparatus and which here takes the form of a tape recorder.

FIG. 24 is a perspective view of the illustrative projector mechanism,here shown disassembled from a supporting base;

FIG. 25 is a perspective view of a silent tilt base suitable forsupporting the projector shown in FIG. 24;

FIG. 26 is a perspective view of a sound control base suitable forsupporting the projector mechanism shown in FIG. 24;

FIG. 27 is a perspective view illustrating the projector of FIG. 24 andthe sound control base shown in FIG. 26, coupled together; and,

FIG. 28 is a perspective view on a reduced scale illustrating the coverfor the sound control base shown in FIG. 26, which cover also serves asa remote speaker during sound equipped programs.

While the invention is susceptible of various modifications andalternative forms, a specific embodiment thereof has been shown by wayof example in the drawings and will herein be described in detail. Itshould be understood, however, that it is not intended to limit theinvention to the particular form disclosed, but, on the contrary, theinvention is to cover all modifications, equivalents and alternativesfalling within the spirit and scope of the invention as expressed in theappended claims.

Housing and support structure Referring now to the drawings, there isillustrated in FIG. 1, an exemplary slide projector particularlysuitable for incorporation of the improved shutter mechanism of thepresent invention. As here illustated, the projector is set up forsilent remote control operation and includes an exterior housing 10mounted on a suitable base 11. For the purpose of supporting slides forseriatim feed through the projector, a slide magazine 12 is mounted inthe top of housing 10. A second magazine 12' identical to the magazine12 is supported beneath the housing 10. A remotely operable multiplesignal control device 13 is plugged into the housing 10 for enabling theoperator to change slides from a point remote from the projector. Asbest shown by reference to FIGS. 6 and 7, the various components of theprojector housing are carried by a generally U-shaped channel 14 whichalso serves as a holder for the removable lower slide magazine 12'(FIGS. 1 and .11). Thus, the channel 14 supports from rear to front(left to right as viewed in FIGS. 6 and 7) a blower housing assembly 15,an L-shaped support bracket 16, a transverse slide transfer track 17 anda slide transfer base plate 18. The base plate 18 serves to support apair of horizontally spaced, vertical slide plates 19, 20 (FIGS. 6 and11) which define a slide hopper, top magazine socket and slide dischargechute. Fastened to the forward portion of the two vertical side plates19 and 20 is a shutter assembly unit which is mounted on a shutterassembly plate 21. An upper track 22 and lower track 23 form a guidewayfor the twin lens support housing 24 and 25 (FIGS. 7, l0 and 20).

Optical system In the illustrative slide projector, provision is madefor minimizing the amount of heat projected towards the slides, thuspreventing warping and damage to the slides. To this end, a pair ofdichroic mirrors 30, 39 are respecly mounted in the paths of the twolight beams passing through lenses 28, 28such mirrors beingcharacterized by their ability to transmit the heat producing infraredradiation in the beams while simultaneously reflecting the coolerradiant energy in the visible light spectrum. The exemplary mirrors 28,28' are mounted in brackets 31, 31 which are rigidly secured to thesupport bracket 16 so as to reflect the visible light in a forwarddirection in two substantially parallel beams. As here shown, themirrors 30, 30 are mounted so as to intercept the respective beamspassing through lenses 28, 28' at an angle of approximately 45.

A second pair of condensers 32, 32' are supported on the vertical leg ofbracket 16 by clips 33 and positioned to transversely intersect theparallel light beams reflected by mirrors 30, 30'. The arrangement issuch that the lenses 32, 32' are respectively alined with slidereceiving apertures 34, 34' formed in the opposite ends of theslidetransfer housing 17 (FIGS. 6 and 11). A shutter assembly plate 35 (FIGS.6 and 10) is provided with light apertures in the path of the twinprojected parallel light beams, The twin optical systems are completedby providing twin projection lenses 36, 36', which are adjustably heldfor both focusing and image alinement by right and left hand supporthousings 24, 25 (FIGS. 7 and 20).

Provision is also made for adjusting the twin light beams so as topermit images projected thereby to be selectively superimposed,overlapped, or juxtaposed in side-by-side relation, all at varyingdistances from the projector. To accomplish this, the exemplaryapparatus includes a wedge block 38 (FIG. 20) which is interposedbetween the twin lens support housings 24, 25 and which slidably engagesthe facing inclined surfaces of the housings. A tension spring 37,having its opposite ends connected to respective ones of the housings24, 25, is provided for urging the housings into intimate engagementwith the wedge block 38. To permit horizontal lens spread adjustment(for both image convergence and sideby-side image presentation atvarying distances), the

Wedge block 38 is coupled with a screw shaft 39 having an integralknurled whel 49. The shaft 39 rotates in a hearing 41 mounted in theshutter assembly plate 21. Thus rotation of the wheel 40 causes verticalmovement of the wedge block 38 with a consequent variation in horizontalspread between the lenses 36, 36. To permit vertical image adjustment,provision is made for slightly raising or lowering the right hand lens36 and its support 24 relative to the lens 36. To this end, a lever 42having a cam '43 is pivotally mounted on the housing 24 with the campositioned to engage the lower track 23. Thus, rotation of lever 42serves to cam the housing 24 and lens 36 in a vertical directionrelative to the track 23, and therefore relative to lens 36'.

Drive mechanism In order to permit selective operation of the slidechanging mechanism, a motor 44 (FIG. 6) is mounted on the rear portionof the blower housing. A blower wheel 45 is fastened to the motor shaft46 for the purpose of cooling the projector. As best iluustrated byreference to FIGS. 6 and 7 conjointly, a flexible coupling 47 mounted onthe motor shaft 46 couples the latter with a drive shaft 48. The shaft48, through a second coupling 47', transmits power to a drive worm andshaft 49. The drive worm and shaft 49 is mounted for rotation inbearings 50 (FIG. 7), the latter being carried by a bracket 51 securedto the vertical side plate 19. The worm 49 is meshed with a drive gear52 which rotates freely on an upper shaft 54 journaled in the sideplates 19, 20, thus permitting a selective power drive for the sidechanging mechanism.

Referring to FIGS. 21 and 22, it will be observed that gear 52 isprovided with a notched hub 53 for selective engagement with a clutchunit 55 rigidly secured to the shaft 54. To drivingly couple the gear 52to the clutch unit 55, a pawl 56 is pivotally secured by a pin 57 to thehousing of the clutch unit. The hook portion of the pawl 56 is normallyurged against the ratchet-like teeth of hub 53 by a spring 58, one endof which is rigidly secured to the housing of clutch unit 55. Fornormally disengaging the driving and driven clutch elements, a latch 59is pivotally mounted on a pin 60 extending through a bracket 61, thelatter being secured to the side plate 19 (FIG. 22). The latch 59 isurged to its innermost position where it engages the pawl56 by means ofa torque spring 62, thus serving to urge the hook portion of the pawlagainst the bias of the spring 58 so as to maintain the clutch in adisengaged position. A release lever 63, also pivoted on pin 68, isprovided with a spring loaded hook 64 for pivoting the latch 59 aboutthe pin 60 (counterclockwise as viewed in FIG. 22) so as to disengagethe latch from pawl 56. To actuate the release lever 63, a solenoid 65(FIGS. 6, 7 and 22) mounted on the shutter assembly plate 21 has itsplunger linked directly to the release lever by .a pin 66.

In operation, when the solenoid 65 is energized, its plunger isretracted, thus pivoting the release lever 63 and hook 64 about pin 60so as to disengage the latch 59 from clutch pawl 56. At this time thepawl 56 is urged by spring 58 into engagement with the ratchet teeth onhub 53 of the drive gear 52. To insure that the clutch and associatedmechanism is limited to a single revolution during each slide changingcycle, a cam finger 67 (FIG. 17) is rigidly mounted on the clutchhousing and positioned to strike the spring loaded hook 64, disengagingthe latter from latch 59. The latch is then biased by spring 62 backinto engagement with pawl 56, disenga ing the latter from the ratchetteeth on hub 53 and uncoupling the driving and driven clutch members.

The upper shaft 54, which is also provided with a knurled knob 68 forpossible manual operation, rotates in bearings 69 (FIG. 22) mounted onthe vertical side plates 19, 20. Rotation of the upper shaft serves toeffect both feeding of slides from magazine 12 (FIGS. 8 and 9) andstacking of slides in the lower magazine 12'. To accomplish the slidefeeding operation, power is transmitted from the upper shaft 54 (FIG.17) to the lower shaft 72 by means of a pinion 70 attached to the uppershaft 54- and a gear 71 attached to the lower shaft 72. The lower shaft72 is mounted for rotation in bearings 73 carried by side plates 19, 20(FIGS. 12). In the exemplary apparatus, the gears 70, 71 are dimensionedsuch that the lower shaft 72 makes /2 revolution for each fullrevolution of the upper shaft 54.

Slide feeding mechanism Referring to FIGS. 6, 11 and 22, there isillustrated an exemplary slide feeding mechanism suitable for use withthe illustrative slide projector. As here shown, the slide feedingmechanism includes the two vertical slide plates 19, 20 which are spacedapart with a divider bar 74 and divider plate 75 (FIGS. 8, 9 and 10).With the addition of guide bars 76, a hopper-like space 77 is providedfor either supporting a stack of slides 78 for projection, or forfurnishing a socket for reception of the slide magazine 12 with itsslides 78. In order to insure bottom support of a stack of slides 78,the divider bar '74 is furnished with a centrally positioned ledge 79.Attached to the inner forward portions of side plates 19, 20 are twonarrow tracks (FIGS. 9 and 22), their upper portions defining with ledge79 a three-point support for the slide stack. The lower portions oftracks 80 define a slide guide, which along with divider plate 75,directs the slides 78 into the slide transfer track 17. Attached to andpositioned over tracks 80 are feeler springs 82, which allow the passageof only one slide at a time regardless of slide thickness. A slideseparating yoke 83 (FIGS. 10 and 22) having a narrow rear blade 84 andtwo forward blades 85 of thickness not more than the thinnest slide,straddles the hopper 77 with its stack of slides 78. The distancebetween the rear blade 84 and forward blades 85 is slightly greater thanthe width of a standard slide mount.

In the illustrative apparatus, provision is made for selectivelystripping the lowermost slide from the stack positioned in hopper 77. Tothis end, yoke 83 is connected by pins 86 to a pair of side arms 87, 87,both of Which are mounted on a shaft 88, which in turn is rotatablyjournaled in bearings 89 (FIG. 12) mounted on side plates 19, 20. Thelower portions of the side arms 87, 87' (FIG. 7) are coupled by pins 99with a lower yoke 91 (FIGS. 7 and 11) which is rigidly connected with aU- shaped slide stacker 92. The rear portion of the yoke 91 is guided inslots 93 formed in the channel 14.

In operation, rotation of the upper shaft 54 (FIG. 10) causes rotationof a cam 94 attached thereto. As the cam 94 rotates, it contacts anupper roller 95 which is mounted on the left hand side arm 87 by meansof a pin 96, thus causing yoke 83 to move forward, its rear blade 84engaging the lowermost slide 78 (FIG. 8) and pushing it off thesupporting ledge 79 (FIG. 9). The feeler springs 82 adjust to thethickness of each slide and hold back the next slide (as shown in FIG.9, the feeding and stacking mechanism has completed /2 cycle). Tocomplete the second of the feeding cycle, the cam 94 (FIG. 10) engages aroller 97 mounted on an overload lever 98 which, through overloadrelease spring 99 is held against side arm 87, thus causing yoke 83 tomove backward from the position shown in FIG.- 9 to that shown in FIG.8. When this occurs, the front yoke blades 85 engage the slide 78causing it to fully separate from the upper slightly inclined stack, thetracks. 80 tipping and directing the separated slide 78 into a receivingstation 100 (FIGS. 8 and 12) in the center of the slide transfer track17. Thus, the slides 78 are fed seriatim from the hopper 77 into thereceiving station 100. I

In the exemplary projector, and as disclosed and claimed in theaforesaid copending Antos application, provision is made for selectivelyshifting the slides 78 laterally from the centrally disposed receivingstation 100 in the slide transfer track 17, with alternate ones of theslides shifted into alinement with different ones of the right and letfhand apertures 34, 34 respectively in the twin optical systems, and forrestacking the slides after image projection in a single container ormagazine 12' in the same order as the slides are fed into the receivingstation, thus insuring that the restacked slides are ready for the nextprogram presentation. As best shown by reference to FIGS. 12 through 16,this is accomplished by providing alternator means for shiftingsuccessive slides positioned in the receiving station 100 in oppositelateral directions in the transfer track 17, and by providing sweepmeans for shifting each slide laterally after image projection, to acentrally disposed discharge station 101 formed in the transfer track 17and alined with the slide magazine 12.

In order to facilitate an understanding of the illustrative slidefeeding apparatus, the mechanism for effecting lateral slide movementwill be described hereinbelow in conjunction with one complete operatingcycle during which an image is projected from one slide in each aperture34, 34. For the purpose of this description let it be assumed thatslides 78a, 78b and 7 8c are initially present at the left hand aperture34, receiving station 100, and right hand aperture 34 respectively (FIG.12). It shall also be assumed that an image has already been projectedfrom the slide 78a in the left hand optical system (i.e., the systemincluding aperture 34') and that an image is now being projected on theviewing screen by the slide 780 in the right hand optical system (i.e.,the

system including aperture 34).

In the apparatus shown merely by way of illustration, provision is madefor sweeping the slide 78a out of the transfer track 17 and replacing itwith a new slide 78b. To accomplish this, a cam 102 is mounted on shaft72 for rotation therewith. A roller 103 is mounted on the cam 102 andpositioned to engage a left lever 104 pivotally mounted on the shaft 88.The arrangement is such that when the shaft 54 begins to rotate, theshaft 72 (through pinion 70 and gear 71) is rotationally driven. Thus,the cam roller 103 engages the lever 104, pivoting the latter aboutshaft 88 (in a clockwise direction as viewed in FIG. 8). As the lever104 pivots, it transmits motion through a connecting link 105 to a sweeparm 106, causing the latter to pivot about a mounting pin 108 rigid withthe base plate 18 (that is, the sweep arm 106 pivots in acounterblockwise direction as viewed in FIG. 12). As the sweep arm 106pivots, its outer tip 107 engages the slide 78a, shifting the latterinto the discharge station 101 formed in the slide transfer track 17(FIG. 13), thus permitting the slide 78a to drop downwardly into themagazine 12' (FIG. 8).

Continued rotation of the shaft 54 and its driving gear 71 causes a camroller 109 mounted on the gear to engage the lower fork 110a of analternator lever 110 (FIG. 8), pivoting the lever 110 about shaft 88. Asthe lever 110 pivots, motion is transmitted through a connecting link113 (FIG. 12), thus pivoting an alternator arm 114 about a pivot pin 112(in a clockwise direction as viewed in FIG. 12). The opposite end of thealternator arm 114 is here coupled to an alternator unit 116 by aconnecting rod 115. Thus, clockwise pivotal movement of the arm 114causes the alternator unit 116 to slide transversely along a track 118from the right hand position shown in FIG. 13 to the left hand positionshown in FIG. 14.

The foregoing action of the alternator unit 116 causes a centrallydisposed shift bar 117 on the alternator unit to engage one edge of theslide 78b in the receiving station 100, pushing it outward to a pointjust beyond a divider wall 119 which separates the receiving anddischarge stations (FIG. 14). Of course, it will be observed that as theslide 78b shifts, it will engage the tip portion 107 of lever 106,pivoting the latter outwardly. To insure that the slides are snappedagainst the transfer housing plate 17 in line with apertures 34, 34', apair of curved slide positioning springs 120, 120" are rigidly mountedon the housing 17 and respectively associated with the apertures 34,34'. Thus, the spring 120' serves to properly position slide 78b (asshown in FIG. 14) in readiness for image projection. During the lastportion of this part of the slide changing cycle, a new slide 78 (FIGS.8 and 9) is dislodged from the hopper 77 and drops into the receivingstation (this slide being represented in FIG. 15 by the identifyingreference numeral 78d), while the slide 78a previously dropped into therear portion of slide magazine 12 is pushed forward thru the movement ofthe slide stacker 92 (FIG. 9). A slide retaining spring latch 121 ispivotably attached at point 122 to the plate 18 in position to engagethe top portion of slide stack in magazine 12 keeping it from tippingback when the stacker 92 moves back to receive another slide.

In order to discharge the slide 78c from the right hand optical systemwhen the operator is finished projecting an image therefrom, the clutch55 is again engaged to initiate a second revolution of the upper shaft54. During the second revolution of the shaft 54, the lower shaft 72 isdriven through the second half of its first complete revolution. As thedrive gear 71 commences this portion of the slide changing cycle, thecam roller 109 contacts a right lever 124 which'is similar to left lever104 and which is also pivotally mounted on shaft 88. As the cam roller109 engages the lever 124, the latter is pivoted about the shaft 88 (ina clockwise direction as viewed in FIG. 9) so as to effect, throughconnecting link 105, clockwise rotation (FIG. 12) of a right hand sweeparm 125. When this occurs, the tip portion 126 of the sweep arm 125engages the outer edge of slide 78c, driving the latter into thedischarge station 101 (FIG. 15).

During the final rotation of gear 71, the roller 109 contacts the upperfork 11012 of the alternator lever 110, pivoting the lever 110 in acounterclockwise direction (as viewed in FIG. 8). As the lever 110'pivots, motion is transmitted through connecting link 113 to alternatorarm 114, pivoting the arm in a counterclockwise direction about pivot112 (FIG. 12) from the inner position shown in FIG. 15 to the outerposition shown in FIG. 16. This motion of the alternator arm 114,through the connecting rod 115, causes alternator unit 116 to move tothe right so that the opposite side of the shift bar 117 engages theinner edge of slide 78d, moving it outward within the confines of slidetransfer housing 17, until the springs 120 dislodge the slide 7 So fromthe divider wall 119 and snap it into alinement with the right handaperture 34 ready for projection. It will be appreciated that during theperiod of time that the discharged slide 78c is being stacked in thelower magazine 12' by the slide stacker 92, a new slide is stripped fromthe bottom of the slide stack in hopper 77 (FIGS. 8 and 9) and droppedinto the receiving station 100, the new slide being represented by theidentifying reference numeral 782 in FIG. 16.

Shutter mechanism and controls embodying the features of the presentinvention In accordance with one of the important aspects of the presentinvention, and for the purpose of permitting selective projection ofimages from one or the other of the twin optical systems while retainingthe capability of selectively blending successive images into oneanother over a controlled blending interval, there is provided a novelshutter mechanism and actuating arrangement therefor. As best shown inFIG. 17, the shutter mechanism includes twin scissor-type shutterassemblies 127, 127' consisting of upper blades 128, 128' and lowerblades 129, 129 respectively (FIG. 17). The blades are all pivotallymounted on the shutter assembly plate 21 (FIG. 6) by means of pins 131.Each pair of upper and lower blades are linked together for synchronizedscissor-type action by means of mating notch and .pin couplings as shownat 130, 130. The inner end of the right hand shutter blade 129 isconnected by a link 132 and a pivot arm pin 136 to a central shuttercontrol lever 133, while the opposite or left hand shutter blade 129' isconnected by a similar link 132' and pivot arm pin 136' to arepositioning lever 134. Both levers are held together by friction andare mounted on the frame at a common pivot point 135. When the maincontrol lever 133 is swung to the right hand position as shown in FIG.17, and the repositioning lever 134 is swung in the opposite direction,the pivot points 136 are placed approximately 90 degrees apart from themain pivot point 135, thus permitting the right hand shutter assembly127 to be wide open and maintaining the opposite or left hand shutterassembly 127'.fully closed.

In order to close the right hand shutter assembly 127 and open the lefthand assembly 127, it is simply necessary to shift the central controllever 133 to the opposite or left hand position (FIG. 18) against thebias of the shutter energizing spring 137. When the lever is released,it will automatically return to its original position, thus permittingthe operator to manually open the shutter for a desirable period oftime. In the case of stereo or wide screen pictures where both imagesmust be projected simultaneously, the repositioning lever 134 ismanually pushed in the same direction as the central shutter controllever 133 until both pivot arm pins 136, 136' are in line (FIG. 19).This will cause the left hand shutter assembly 127' to open at the sametime as the opposite or right hand assembly 127. Thereafter, movement ofcentral control lever 133 will cause both shutter assemblies to closeand open again in unison, both shutters closing just before the firstslide is changed and opening again just after the second new slideappears in place. Also, in the case of stereo pictures, provision ismade for mounting suitable filters (not shown) in the optical systems.To this end, filter supporting brackets 198 are mounted on the shutterassembly plate 21 (FIG. 7).

In accordance with another of the important aspects of the presentinvention, provision is made for blending the images projected by thetwin optical systems during a slide changing cycle so as to eliminateundesirable and irritating blackout periods between consecutive slides.Preferably the blend time is selectively variable so as to permit a widerange of interesting special effects. To per mit shutter blending atvarious speeds, a speed retarder unit. 143 (FIGS. l0, l7 and 18) ismounted on top of the shutter assembly plate 21. In the exemplary formof the invention, the retarder unit includes a vertical spindle 144 onwhich a retarding hub 145 is rotatably mounted. The hub 145 is directlycoupled to the central shutter control lever 133 by a lever 146 integralwith the hub and a connecting link 147.

Referring more particularly to FIG. 18, it will be observed that the hub145 is spaced from an upper intermediate motion retarding wheel 149 by amedium size area of silicone compound 148. Similarly, the hub 145 isspaced from a lower slow motion retarding wheel 150 by a large size areaof silicone compound 151. A dual finger lever 152 is pivoted to theretarder unit 143 at point 153 and held in position by frictionalcontact. For the purpose of actuating the lever 152, a sequence selectorrod 154 is slidably and pivotably mounted in bearings 111 carried byplate 21 (FIG. 6). The sequence selector rod 154 is coupled to the lever152 by means of a connecting arm 155 and link 156 (FIGS. 6 and 17).

In normal operation, the remote multiple signal control unit 13 (FIGS. 1and 23) is plugged into a circuit including the solenoid 65. As bestshown in FIG. 23, the remote control unit 13 comprises a microswitch 138coupled with a time delay unit 139 (here shown as including an hydraulicdashpot) and push buttons for instant contact 140, intermedite contact141 and delayed contact 142. The arrangement is such that when thebutton 140 is depressed, the microswitch 138 is momentarily closed, thuscompleting an energizing circuit for the solenoid 65 and momentarilyengaging the clutch 55, thereby causing a single rotation of the shaft54 as previously described. As the clutch housing 55 rotates, the camfinger 67 mounted thereon engages the inwardly projecting end 154a ofsequence selector rod 154, thus camming the rod to its downward limit(counterclockwise as viewed in FIG. 7). This causes the upper finger152a of dual finger lever 152 to engage the intermediate motionretarding wheel 149.

Continued rotation of the shaft 54 causes a cam wheel 157 mountedthereon (FIGS. 6, 10 and 17) to lift up on a shutter brake rod 158pivoted in side plates 19, 20. When this occurs, a projecting portion158a of the brake rod 158 is pushed against the shutter control levers133, 134 (FIG. 10), thus preventing operation of the shutters during theintermediate portion of the slide changing cycle.

' Further rotation of shaft 54 will cause the lower shaft 72 with itsshutter cocking cam 102 to rotate from a down position (right handshutter 127 open) as shown in FIG. 17, to an up position (left handshutter 127 open) as shown in FIG. 18. This cams a spring anchor bracket160 (which is mounted on the side plate 20 with freedom for verticalmovement relative thereto) upward above pivot point 135, thus loadingthe shutter energizing spring 137 until it tends to pull shutter controllever 133 into the opposite direction. At the completion of the slidechanging cycle, the cam wheel 157 allows shutter brake rod 158 toreleaseits hold on the shutter control levers 133 and 134, therebypermitting the spring 137, which is anchored at one end to the bracket160 and at the other end to the lever 133, to initiate a shutterreversing operation. When the control levers 133, 134 begin to shift,motion is imparted to the retarding hub through the connecting linkage146, 157. Since the upper intermediate motion retarding wheel 149 isengaged with the hub and at the same time locked against rotation byfinger 152a, there is a slight retarding frictional drag between the twodue to the small silicone retarding surface 148'. This produces anintermediate blending action of approximately 1% seconds durationbetween the change from one projected image to the next (as shownbetween FIGS. 17 and 18).

One of the important features of the invention is that the blendingaction described above can be selectively varied by the operator toprovide substantially instantaneous image changing, image blending foran intermediate length time interval (e.g., 1% seconds as describedabove), or a relatively long blending time interval (e.g., forapproximately 7 seconds). To permit substantially instantaneous changingof successive projected images, the medium contact button 141- (FIG. 23)is depressed, thus pivoting the time delay link 139a about pivot 13% andclosing the contacts for the microswitch 138. It will be appreciatedthat depression of button 141 as opposed to button 140, causes greaterpivotal movement of the link 139a, with a consequent greater retractionof the plunger within the dashpot 139. Therefore, more time is requiredfor the link 139a to return to the solid line positron shown in FIG. 23.As a result, the microswitch 138 remains closed for a greater length oftime and the solenoid 65 remains energized long enough to allow lever 63(FIGS. 6, 7 and 17) to contact an overpower compression spring 162, thuspushing the sequence selector rod 154 inward so that its inwardprojecting portion 154a is positioned to be engaged by a second cam 163mounted on the face of the clutch unit 55. As the clutch unit 55rotates, the tip portion 154a of rod 154 rides up on the cam surface163a of cam 163. The arrangement is such that the solenoid 65 isdeenergized during the period when the rod 154 is in contact with thecam surface 163a, thus disengaging lever 63 from spring 162 andpermitting the rod 154 to shift outwardly. This serves to disengage thetip 154a from the cam surface 163a at an intermediate point of thecycle, thereby positioning the dual finger lever 152 in an intermediateor neutral position so as to permit both the upper retarding wheel 149and the lower retarding wheel 150 to free wheel with the retarding hub145. Under these conditions, there is no retarding action, thus allowingthe projected image to change instantly. The shutter assemblies 127,127' reverse substantially instantaneously so as to change images withno intervening blackout period.

To produce still another desirable effect, for example, a very slowblend, the delay contact button 142 is depressed (FIG. 23). This causesenergization of the solenoid 65 for a length of time equal to orsomewhat longer than a single slide change cycle. As a result the tipportion 154a of rod 154 rides up on the peak portion 161% of the cam 163during the final portion of the single rotational cycle of clutch unit55 so as to lift the sequence selector rod 154 to its upward limit (FIG.6). When this occurs, the dual finger lever 152 is pivoted about point153 so as to cause the lower finger 152b to engage the Slide magazineReferring now to FIGURES 1-5, there is illustrated an exemplary slidemagazine 12 which fiinds particularly advantageous use with the slideprojector described above. As here shown, the magazine 12 is-of the openend type suitable for stack feeding and also suitable for storing largenumber of slides. While it will be appreciated that the magazine 12 canbe built to any desired length, it has been found that a magazine havinga capacity of 100 to 200 slides appears to be most practical. Theillustrative magazine 12 is substantially square (FIG. 2), comprising a"bottom and two sides, the top side being open to permit ready accessfor either group loading or rearranging and removal of slides 78, suchas i necessary in editing a program. Both upper portions of the slidemagazine 12 are formed into tracks 164 for slidably receiving a U-shapedspring loaded slide retainer 166 which holds the slides tight againstthe flanges 165 at the opposite end of magazine. A top cover 167 (FIG.4), prefer-ably made of clear plastic with molded ratchet-like teeth1'68, engages and locks the slide retainer 166 in place when it isnapped over the magazine 12. This construction permits large numbers ofslides to be economically stored, at the same time staying flat and dustfree. The slide stack, since it is held tightly together, can be markedon top with one or more diagonal lines 169 (FIG. 2) for visualidentification and verification of slide sequences. To load the magazine12 into the projector, the cover 167 is removed, the open end (oppositeflanges 165) is inserted into the hopper portion 77 of the projector,and the U- shaped retainer 166 is squeezed together and removed, thusallowing the slides to feed freely into the mechanism. A second emptymagazine 12' having a slide retainer 166 in place, is then inserted intothe channel 14 of the slide projector for the purpose of receivingslides discharged from the discharge station 101.

Plug-in arrangement for synchronization with sound control base When theillustrative slide projector is used in presenting a silent slideprogram, the housing unit 10 is usually furnished with an accompanyingsilent tilt base unit 11. The base 11 is here provided with apositioning channel 170 (FIG. which permits locating and locking of bothunit together. The bottom of the base 11 is further provided with rubberpositioning feet 171, the forward ones being adjusta'bly positioned topermit selective front elevation of the projector. A suitable cover 172(indicated by a broken line in FIG. 25) is fastened over the base 11 andoffers protection for the projector unit 10 while also serving as aconvenient carrying case.

Provision is also made for readily plugging the projector 10 into amatching sound control base 173 which permits fully automated soundprojection. To thi end, the base 173 is formed with a necessary cutout174 to fit under and receive the channel 14 on the projector assembly 10(FIGS. 26 and 27). Electrical connections conveniently take the form ofa multiple plug connector 175 in the bottom portion of the projectorhousing 10 (FIGS. 23 and 24) and a matching socket 176 located in theupper portion of the record unit 173 (FIGS. 23 and 26). The controlrecorder unit 173 may also be provided with a screw type adjustable foot177 at the rear for side tilt control and a center front elevationcontrol foot 123, operable thru knob 178 (FIGS. 26 and 27). The soundcontrol base 173 is also provided wtih a detachable cover shown inreduced scale in FIG. 28) having a built in peaker 179. In operation,the speaker 179 permits sound to come from the area of the projectedimage (i.e., from the vicinity of the viewing screen). The cover 180 isbuilt to fit over the combined sound slide blending projector unit so asto serve both as a protective medium and a carrying case. As shown inFIG. 27, the tape transport mechanism of the recorder unit 173 isgenerally of convenient construction. However the control panel ispreferably positioned vertically with controls grouped between thereels.

Referring to the schematic wiring diagram in FIG. 23, both controlsignal and accompanying sound are carried side by side on a standardribbon of tape 181. Between the two reels 182, a transducer head 183 ispositioned to contact one half of the tape. A recording and playbackamplifier 184 is coupled to the transducer head 183 and separablycoupled to the solenoid 65 through the plug 175 and receptacle 176. Theremote multiple signal control unit 13 is connected with the circuit bya connector 185, thus permitting recording of variable length signals. Arectifier 186 and a condenser 187 are provided in the solenoidenergizing circuit for changing the alternating current to direct, thuseliminate solenoid chatter. A second transducer head 188 is positionedto contact the other half of the tape 181 while an audio amplifier 189is connected between the transducer head 188 and the speaker 179.

While both the projector 10 and the control recorder unit 173 may derivetheir power from one common power input 194, the projector 10 isprovided with a second power input 193 which can be used when theprojector is mounted on a silent tilt base 11. A three way switch 195permits turning on the blower 45 and mechanism only (FIG. 23) or,alternatively, the blower and mechanism plus lamp. Another manual switch196 is provided for electively turning on full light value, or partiallight level thru resistor 197.

While the invention has been described in connection with a novelapparatus for projecting slide images upon a viewing screen, thoseskilled in the art will appreciate that the sequence of operationsdescribed herein also define a novel method for feeding slides seriatimfrom a single supply stack through a twin lens projector assembly, andthence seriatim to a single discharge stack where the successive slidesare stacked in the same order in readiness for the next programpresentation. Such novel apparatus and method form the subject matter ofthe aforesaid copending Antos application. In carrying out such method,a plurality of slides are first arranged in a single stack to form aparticular program. The slides are then successively stripped from thestack and fed seriatim to a receiving station where alternate slides areshifted laterally to difierent ones of twin optical systems. Images areselectively projected either alternately from the twin optical systemsor simultaneously therefrom (if stereo or wide screen presentation isdesired). The slides are then shifted laterally in successive order to acommon discharge chute, from where they fall by gravity into a commondischarge magazine and are stacked in the original program order. Duringshifting of the slides, the operator may selectively vary the durationof the image blending periods.

I claim as my invention:

1. A shutter assembly for use with a slide projector of the typeemploying twin optical systems comprising, in combination, a pair ofshutter mechanisms respectively associated with different ones of saidtwin systems, means forselectively and alternately opening and closingsaid shutter mechanisms, means for controlling said shutter mechanismsso that closure of one of said mechanisms is accompanied by openingofthe other of said mechanisms with at least one of said mechanisms openat all times, and operator controlled means for selectively controllingthe time required for said shutter mechanisms to shift between open andclosed states so that said shutter mechanisms may be selectively shiftedat either of relatively fast and relatively slow speeds.

2. A shutter assembly as set forth in claim 1 further characterized inthat said means for controlling the time required for said shuttermechanisms to shift comprises a retarder unit, said retarder unitincluding means for establishing selectively one of diverse retardingforces and means for remotely selecting a desired retarding force.

3. A shutter assembly as set forth in claim 1 further characterized inthat means are provided for biasing said shutter mechanisms into aselected one of the two alternate conditions with one of said mechanismsopen.

4. A shutter assembly as set forth in claim 3 further characterized inthat manually operable means are provided for selectively overcomingsaid biasing means for a selectable period of time so as to open andclose respective ones of the closed and open shutter mechanisms whilethe latter are urged toward their closed and open conditionsrespectively by said biasing means.

5. A shutter assembly as set forth in claim 4 further characterized inthat said means for selectively and alternately opening and closing saidshutter mechanisms includes means for shifting said biasing means so asto bias said shutter mechanisms into the other of the two alternateconditions with the other of said mechanisms open, said manuallyoperable means for selectively overcoming said biasing means for aselectable period of time so as to open and close respective ones of theclosed and open shutter mechanisms while the latter are urged towardtheir closed and open conditions respectively by said biasing meansbeing effective irrespective of the position of the latter.

6. A shutter assembly as set forth in claim 1 further characterized inthat said means for controlling the time required for said shuttermechanisms to shift includes first selectively operable control meansfor permitting substantially instantaneous shifting of said shuttermechanisms between their open and closed states, and at least one secondselectively operable control means for permitting retarded shifting ofsaid shutter mechanisms between their open and closed states.

7. A shutter assembly as set forth in claim 1 further characterized inthat said means for controlling the time required for said shuttermechanisms to shift includes first selectively operable control meansfor permitting substantially instantaneous shifting of said shuttermechanisms between their open and closed states, second selectivelyoperable control means for permitting retarded shifting of said shuttermechanisms between their open and closed states whereby said mechanismsare both at least partially open during a first relatively short blendinterval, and third selectively operable control means for permittingretarded shifting of said shutter mechanisms between their open andclosed states whereby said mechanisms are both at least partially openduring a second relatively long blend interval.

8. The combination set forth in claim 6 further characterized in thatsaid first and second selectively operable control means are remotelyoperated on a selective basis by a proiectionist.

9. For'use with a slide projector of the type employing twin projectionlenses, the combination comprising, a shutter assembly plate, a pair ofshutter mechanisms respectively associated with different ones of saidtwin lenses, each of said mechanisms including paired upper and lowershutter blades with all of said blades pivotally mounted on said plate,means coupling the upper shutter blade of each pair to its paired lowershutter blade for insuring synchronized scissor-type action of eachshutter mechanism, control lever means piv-otally mounted on said plate,means coupling said control lever means to at least one blade in eachpair with one of said blade pairs open and the other of said blade pairsclosed so that pivotal movement of said control lever means causes saidopen blade pair to close and said closed blade pair to simultaneouslyopen, and operator controlled means for selectively controlling the timerequired for said blade pairs to shift between open and closed states sothat said blade pairs may be selectively shifted at either of relativelyfast and relatively slow speeds.

10. The combination set forth in claim 9 further characterized in thatmeans are provided for pivoting said control lever means between a firstlimit position with one of said blade pairs open and the other of saidblade pairs closed and a second limit position with the states of saidblade pairs reversed, said operator controlled means comprisingselectively operable retarder means coupled to said control lever meansfor controlling the time interval required to shift said control levermeans between said first and second limit positions.

11. The combination set forth in claim 9 further comprising a springanchor bracket adapted to be mounted on said projector with freedom formovement between spaced limit positions, a spring having its oppositeends bottomed on respective different ones of said bracket and saidcontrol lever means, said spring adapted to bias said control levermeans in one direction about its pivot when said bracket is in one ofsaid limit positions and in the opposite direction about its pivot whensaid bracket is in the other of said limit positions, and means forselectively shifting said bracket between its limit positions 'so as toalternately reverse the closed and open states of said shuttermechanisms.

12. The combination as set forth in claim 11 further characterized inthat selectively operable retarder means are coupled to said controllever means for opposing the biasing force provided by said spring andthus controlling the time interval required to shift said shuttermechanisms from one to the other of their closed and open states.

13. The combination as set forth in claim 12 further characterized inthat cyclically operable braking means are provided for momentarilypreventing pivotal movement of said control lever means upon shifting ofsaid bracket from one to the other of its limit positions.

14, The combination as set forth in claim 12 further characterized inthat said selectively operable retarder means includes (1) a firstfriction retarding device for establishing a relatively short intervalof time required to reverse said shutter mechanisms, (2) a secondfriction retarding device for establishing a relatively long interval oftime required to reverse said shutter mechanisms, and (3) projectionistcontrolled means for selectively activating one of said first and secondretarding devices while deactivating the other of said first and secondretarding devices so as to permit retarded reversal of said shuttermechanisms during a selected one of two different controlled timeintervals and for alternatively and selectively deactivating both ofsaid retarding devices so as to permit substantially instantaneousreversal of said shutter mechanisms.

15. The combination as set forth in claim 9 further characterized inthat said control lever means includes first and second control leversmounted on said plate for pivotal movement about a common pivot andmeans coupling said first and second control levers to respectivedifferent ones of said pairs of shutter blades, said first and secondcontrol levers being frictionally engaged with one another for pivotalmovement in unison and free for limited pivotal movement relative to oneanother bet-ween a first frictionally engaged position with one pair ofshutter blades open and the other pair closed and a second frictionallyengaged position with both pairs of shutter blades occupying one of theclosed and open states, whereupon pivotal movement of said levers inunison while in said first frictionally engaged position causes one ofsaid shutter mechanisms to close while the other of said shuttermechanisms simultaneously opens, and pivotal movement of said levers inunison while in said second frictionally engaged position causes both ofsaid shutter mechanisms to simultaneously shift from one to the other ofthe closed and open positions with both shutter mechanisms closing andopening in unison.

16. The combination as set forth in claim 15 further characterized inthat means are provided for pivoting said first and second controllevers between first and second limit positions so as to simultaneouslyreverse the closed and opened positions of said shutter mechanisms, andselectively operable retarder means coupled to one of said controllevers for controlling the time interval 1 6 required to shift saidcontrol levers between said first and second limit positions.

References Cited by the Examiner UNITED STATES PATENTS 450,815 4/ 1891McClintock 88-28 947,471 1/1910 Klaiber 88-28 968,667 8/1910 Klaiber.1,365,752 1/1921 Vischer 88-28 1,738,943 12/1929 Brenkert et al.2,259,651 10/1941 McClure -2- 352-34 2,448,220 8/ 1948 Jenkins 352-1352,528,855 11/1950 Cadwell et al. v 2,530,417 11/1950 Young 88-282,655,833 10/1953 Krows 352-210 2,705,439 4/1955 Waller 88-28 2,922,3351/1960 Laooe 88-28 2,942,365 6 1960 Badalich -79 2,973,689 3/1961 Bailey88-28 3,014,296 12/ 1961 Walter 40- 97 3,033,077 5/1962 Schwartz et al.88-28 3,093,030 6/1963 Carrillo 352-198 X NORTON ANSHER, PrimaryExaminer.

H. H. FLANDERS, Assistant Examiner.

1. A SHUTTER ASSEMBLY FOR USE WITH A SLIDE PROJECTOR OF THE TYPEEMPLOYING TWIN OPTICAL SYSTEMS COMPRISING, IN COMBINATION, A PAIR OFSHUTTER MECHANISMS RESPECTIVELY ASSOCIATED WITH DIFFERENT ONES OF SAIDTWIN SYSTEMS, MEANS FOR SELECTIVELY AND ALTERNATELY OPENING AND CLOSINGSAID SHUTTER MECHANISMS, MEANS FOR CONTROLLING SAID SHUTTER MECHANISMSSO THAT CLOSURE OF ONE OF SAID MECHANISMS IS ACCOMPANIED BY OPENING OFTHE OTHER OF SAID